Compressed-air engine.



D. R. MURPHY. I COMPRESSED AIR ENGINE. APPLIOATION F ILBD JULY 31,1911.

Patented Apr. 30, 1912.

2 SHEET4S SHEET 1.

WITNESSES.

COLUMBIA PLANOGRAPH cm. WASHINGTON. D. c.

1). RpMU'RPfiY. COMPRESSED AIR ENGINE. APPLICATION FILED JU LY 31,1911,

Patented Apr. 30, 1912.

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INVENTOR.

' COLUMBIA PLANOGRAPH 10., WASHINGTON. u. c.

UNITED STATES PATENT OFFICE. I

DANIEL R. MURPHY, OF FREDERICKTOWN, PENNSYLVANIA, ASSIGNOR- '10 H. K. PORTER 00., OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

COMPRESSED-AIR ENGINE.

To all whom it may concern:

Be it known that I, DANIEL R. MURPHY, a citizen of the United States, and resident of Fredericktown, in the county of WVashington and State of Pennsylvania, have in vented a new and useful Improvement in Compressed-Air Engines; and I do hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to compressed air engines. Its object is to improve on a construction hitherto employed in certain types of these engines, in which stop valves are provided in the connection between the air reservoir and the initial or high pressure cylinder, the said connection being provided with a reducing valve to reduce the pressure of air entering the valve chest from that of the reservoir pressure to a uniform working point. As hitherto constructed, such engines, as applied to a locomotive, have been provided with a stop valve in front of the reducing valve, which has been controlled in general by an auxiliary air pipe actuating a piston connected to the valve. The purpose of such a stop valve is to prevent the piling up or increase of pressure when the engine is not using air in the connection leading from the reducing valve to the cylinder, and between the throttle valve controlling such connection and the reducing valve itself. This increase of pressure in such connection and the auxiliary reservoir usually included therewith is caused by the leakage of air through the reducing valve, on account of the necessary construction of the same; and results in an excessive pressure of air being admitted to the cylinder when the throttle valve is again opened.

By my invention, I improve on the means hitherto employed for actuating the said stop valve, my invention contemplating its actuation purely by mechanical means operated directly by the throttle lever which controls the throttle valve, so that the stop valve moves in unison with the throttle valve, said means comprising preferably a cam carried by a shaft or rod rotated or oscillated by the throttle lever, and a lever actutaed by said cam and actuating the valve stem of the stop valve employed. v

My invention also consists in the construction and arrangement of parts as more particularly described and claimed below.

Specification of Letters Patent.

Application filed July 31, 1911,

Patented Apr. 30, 1912.

Serial No. 641,526.

In the, accompanying drawings Figure 1 is an end view illustrating my invention as applied to compressed air locomotive engines. Fig. 2 is a side view partly broken away of the same. Fig. 8 is a detail side elevation partly in section illustrating the cam and lever, valve actuating mechanism, and Fig. 4 is a detail vertical section through the stop valve.

In the said drawings, the compressed air locomotive engine illustrated is provided with a suitable frame 1 and driving wheels 2 on the rails 3. The said engine has the main air reservoir 5. the high pressure cylinder 6, and the connection 7, 7 leading from the air reservoir 5 to the cylinder 6. As illustrated, the connection 7, 7 comprises the pipe 7 opening into the auxiliary reservoir 8 and the pipe 7 leading therefrom to the valve chest 9. The elbow 10 leads di rectly from the reservoir 5 through the casing 11 of the stop valve 11, and through the reducing valve 12 to the pipe 7. The reducing valve 12 shown is of an ordinary adjustable pattern now well understood in the art, being provided with the controlling spring 1 1 and other parts necessary to its operation which will not be specifically described herein. I have also illustrated an interheater 15 to which the exhaust of the cylinder 6 is connected by a pipe 13, the interheater 15 being connected by the pipe 13 with the valve chest 19 of the low pressure cylinder 20, although the construction and arrangement forms no part of my present invention.

The stop valve 11 has the valve stem 21 which extends through the valve casing 11, being provided preferably with a reduced portion 21 joining the valve head 11 within said valve casing. The effective area, or upper pressure face of the stop valve 11, above the valve seat 22, is thus much greater than the effective area of its opposite pressure face, the difference being substantially equivalent to the horizontal cross section of the portion 21 of the valve stem 21, when the valve is open. There is, therefore, during normal operation of the engine, a force tending to close this valve 11 substantially equal to the product of the pressure per unit area within the reservoir 15 times the cross section of said valve stem portion 21. When the valve is closed through the withdrawal of supportt'rom the valve stem 21, as described below by the said pressure, how ever, the pressure within the connection 7, T and reducing valve 12 being in general much than that of the reservoir, andv in tact it'requently atmospheric only when the engine is dis-used for a time, the ditl'erence in pressures is thereby greatly accentuated on the opposite sides of the valve 11. It therefore requires a very great force to raise this valve 11 from this seat although after a material opening is produced, the force necessary is greatly reduced. l therefore provide means, as described below for obtaining a very slow initial opening of the valve 11. and. tor acceleratii its further opening. The valve 11 is raised from such seat by means of the am 23 which is carried on a rotating or oscillating shaft 21: with which the throttle lever is provided. The said shatt 2 t is jinninaled. in the bearings 18 attached to the haromotive frame 1, and the cam 22. is fastened to it preferably by the screw 26 or in any desired itashion. lhe valve stem 21 is provided preferably with a clevis 21' through which extends the lever 28 pivotally connected thereto by the pin 29 held in position by the head 30 and cotter pin 31. The clevis 2? mreterably screwed onto the valve rod 21 at 27, as shown. The

arm 28 of the lever 28 is actuated by the cam 2 being preferably provided with an antitriction roller 232 along which the said cam plays. The 01))OSll'G end of the lever 28 is fulcrumed by the pin 33 to the adjustable clevis-head 3-1- attached to the clevis rod 5-35. The said clcvis-head 341-. is provided with the adjusting nut 36 and the lock nut 88, which thread on the clevis-rod 35, which is in turn screwed. into the lug 39 of the valve casing 11 at. a l). The clevis-head 3i, and hence the fulcrum-point of the lever 28 is adjustable by means of the said nuts 36 and 38; so that the closure of the valve 11 can be nicely regulated.

The throttle lever 25 is connected through the shaft 24-, the arm 41. the connecting rod 12, and the arm i?) to the throttle valve .1 as illustrated in Figs. 1 and The throttle lever 25 is also preferably provided with the usual latch and handle device 15 and segment rack to.

In operation, when it is desired to start the engine, the throttle lever 25 is moved to open the throttle valve ill. The same movement simultaneously rotates the shaft 2st and cam thereby *aising the stop valve 11, and. permitting air from the reservoir 5 to pass through the reducing valve 12 and auxiliary reservoir 8 to the cylinder 6. During normal operation the reducing valve 12 continuously reduces the pressure to, say about 250 pounds per square inch in the auxiliary reservoir, the pressure in the main reservoir being much higher, say from 800 to 900 pounds per square inch. It, when the throttle is closed, there were no means for preventing the traveling ot the air pastthe reducing valve 12 the pressure in the auxiliary reservoir 8 and pipe 7, 7, would rapidly rise to that of the main reservoir; and upon the throttle valve 1-1- being opened, atremendous gust or blast oft air at excess pressure would be admitted to the cylinder 6. By providing the stop valve 11 which is closed at the same time as the throttle valve at, I prevent the pressure ever rising above the desired maximum amount leyoml the reducing valve 12. My invention provides a simple and eltcctive means for accomplishing this object instantaneously upon the closing of the throttle valve. By my invention, also, owing to the shape of the cam 23 employed the initial movement of the valve 11. is slight or very short compared to the travel of the throttle lever in the same time. T his enables the throttle lever to be readily operated, and would be impossible by other direct mechanical connection than a cam or its equivalent, as the tremendous reservoir presure on the valve 11 opposing its opening would create too great resistance to the movement of the throttle lever. As indicated by the shape of the cam 23, the further movement of the valve 11, after an opening for the assage of air has been provided, can be readily accomplished at a. higher rate oit speed, the cam 23 thus being arranged to impart an accelerating movement to the valve 11.

lVhat I claim is:

1. ln compressed air engines, the combi nation of a compressed air reservoir, an engine cylinder, a connection leading from said reservoir to said cylinder, a reducing valve in said connection, a throttle valve in said connect-ion between said reducing valve and said. cylinder, at stop valve in said connection bet-ween said reducing valve and said reservoir, and a throttle lever controlling said throttle valve and provided with mechanical means for moving said stop valve when actuated.

2. In compressed air engines, the combination of a compressed air reservoir, an engine cylinder, a. connection leading from said reservoir to said cylinder, a reducing valve in said connection, a throttle valve in said connection between said reducing valve and said cylinder, a stop valve in said connection between said reducing valve and said reservoir, a throttle lever actuating said throttle valve, a cam actuated by said throttle lever, and a valve rod connected to said stop valve and actuated by said cam, sub stantially as described.

3. In compressed air engines, the combination of a compressed air reservoir, an engine cylinder, a connection leading from said reservoir to said cylinder, a reducing valve nection, a throttle valve in said connection between said reducing valve and said cylinder, a stop valve in said connection between said reducing valve and said reservoir, a throttle lever cont-rolling said throttle valve, a shaft journaled in the engine frame, carrying said throttle lever and provided with a cam, and a lever actuated by said cam and connected to said stop valve, substantially as described.

5. In compressed air engines, the combination of a compressed air reservoir, an engine cylinder, a connection leading from said reservoir to said cylinder, a reducing valve in said connection, a throttle valve in said connection between said reducing valve and said cylinder, a stop valve in said connection between said reducing valve and said reservoir, a throttle lever controlling said throttle valve, a shaft journaled in the engine frame, carrying said throttle lever and provided with a cam, a lever, and an adjustable fulcrum carrying the same, said lever being movable by said cam, and saidstop valve having a stem pivoted to said lever.

6. In compressed air engines, the combination of a compressed air reservoir, an engine cylinder, a connection leading from said reservoir to said cylinder, a reducing valve in said connection, a valve controlling said connection between said reservoir and said reducing valve, a controlling lever, and mechanism directly connecting the same to said last mentioned valve including a cam adapted to progressively actuate said valve, substantially as described.

7. In compressed air engines, the combi nation of a compressed air reservoir, an engine cylinder, a connection leading from said reservoir vto said cylinder, a stop valve in said connection having opposite pressure faces of different areas, a throttle valve in said connect-ion between said stop valve and said cylinder, a controlling lever, an actuating mechanism connecting said lever to said throttle valve and connecting said lever to said stop valve including a cam adapted to open said stop valve at accelerating speed against the pressure of air on its pressure face of greater area, substantially as described.

In testimony whereof, I the said DANIEL R. MURPHY have hereunto set my hand.

DANIEL It. MURPHY.

W'itnesses ROBERT C. TOTTEN, J. R. KELLER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, I). G. 

